Backlighting causing flickering
This is due to how the Eevee renderer actually functions. Eevee doesn't act like the real world. That's what cycles is for (raytracing). Eevee only works with direct lighting and reflectoins (such as on the dna strand) are 'guessed' by Eevee. It's hard to explain, but if you want to know more about why such artifacts happen in the Eevee renderer, check this video:
Next-Gen Ray Tracing Demo using Blender 3D - How Will It Work?